// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/v8.h"

#include <fstream>

#include "src/api.h"
#include "src/base/atomicops.h"
#include "src/base/once.h"
#include "src/base/platform/platform.h"
#include "src/bootstrapper.h"
#include "src/cpu-features.h"
#include "src/debug/debug.h"
#include "src/deoptimizer.h"
#include "src/elements.h"
#include "src/frames.h"
#include "src/interface-descriptors.h"
#include "src/isolate.h"
#include "src/libsampler/sampler.h"
#include "src/objects-inl.h"
#include "src/profiler/heap-profiler.h"
#include "src/runtime-profiler.h"
#include "src/simulator.h"
#include "src/snapshot/natives.h"
#include "src/snapshot/snapshot.h"
#include "src/tracing/tracing-category-observer.h"
#include "src/wasm/wasm-engine.h"

namespace v8 {
namespace internal {

    V8_DECLARE_ONCE(init_once);

#ifdef V8_USE_EXTERNAL_STARTUP_DATA
    V8_DECLARE_ONCE(init_natives_once);
    V8_DECLARE_ONCE(init_snapshot_once);
#endif

    v8::Platform* V8::platform_ = nullptr;

    bool V8::Initialize()
    {
        InitializeOncePerProcess();
        return true;
    }

    void V8::TearDown()
    {
        wasm::WasmEngine::GlobalTearDown();
#if defined(USE_SIMULATOR)
        Simulator::GlobalTearDown();
#endif
        CallDescriptors::TearDown();
        ElementsAccessor::TearDown();
        RegisteredExtension::UnregisterAll();
        FlagList::ResetAllFlags(); // Frees memory held by string arguments.
    }

    void V8::InitializeOncePerProcessImpl()
    {
        FlagList::EnforceFlagImplications();

        if (FLAG_predictable && FLAG_random_seed == 0) {
            // Avoid random seeds in predictable mode.
            FLAG_random_seed = 12347;
        }

        if (FLAG_stress_compaction) {
            FLAG_force_marking_deque_overflows = true;
            FLAG_gc_global = true;
            FLAG_max_semi_space_size = 1;
        }

        if (FLAG_trace_turbo) {
            // Create an empty file shared by the process (e.g. the wasm engine).
            std::ofstream(Isolate::GetTurboCfgFileName(nullptr).c_str(),
                std::ios_base::trunc);
        }

        // Do not expose wasm in jitless mode.
        //
        // Even in interpreter-only mode, wasm currently still creates executable
        // memory at runtime. Unexpose wasm until this changes.
        // The correctness fuzzers are a special case: many of their test cases are
        // built by fetching a random property from the the global object, and thus
        // the global object layout must not change between configs. That is why we
        // continue exposing wasm on correctness fuzzers even in jitless mode.
        // TODO(jgruber): Remove this once / if wasm can run without executable
        // memory.
        if (FLAG_jitless && !FLAG_abort_on_stack_or_string_length_overflow) {
            FLAG_expose_wasm = false;
        }

        base::OS::Initialize(FLAG_hard_abort, FLAG_gc_fake_mmap);

        if (FLAG_random_seed)
            SetRandomMmapSeed(FLAG_random_seed);

        Isolate::InitializeOncePerProcess();

#if defined(USE_SIMULATOR)
        Simulator::InitializeOncePerProcess();
#endif
        CpuFeatures::Probe(false);
        ElementsAccessor::InitializeOncePerProcess();
        Bootstrapper::InitializeOncePerProcess();
        CallDescriptors::InitializeOncePerProcess();
        wasm::WasmEngine::InitializeOncePerProcess();
    }

    void V8::InitializeOncePerProcess()
    {
        base::CallOnce(&init_once, &InitializeOncePerProcessImpl);
    }

    void V8::InitializePlatform(v8::Platform* platform)
    {
        CHECK(!platform_);
        CHECK(platform);
        platform_ = platform;
        v8::base::SetPrintStackTrace(platform_->GetStackTracePrinter());
        v8::tracing::TracingCategoryObserver::SetUp();
    }

    void V8::ShutdownPlatform()
    {
        CHECK(platform_);
        v8::tracing::TracingCategoryObserver::TearDown();
        v8::base::SetPrintStackTrace(nullptr);
        platform_ = nullptr;
    }

    v8::Platform* V8::GetCurrentPlatform()
    {
        v8::Platform* platform = reinterpret_cast<v8::Platform*>(
            base::Relaxed_Load(reinterpret_cast<base::AtomicWord*>(&platform_)));
        DCHECK(platform);
        return platform;
    }

    void V8::SetPlatformForTesting(v8::Platform* platform)
    {
        base::Relaxed_Store(reinterpret_cast<base::AtomicWord*>(&platform_),
            reinterpret_cast<base::AtomicWord>(platform));
    }

    void V8::SetNativesBlob(StartupData* natives_blob)
    {
#ifdef V8_USE_EXTERNAL_STARTUP_DATA
        base::CallOnce(&init_natives_once, &SetNativesFromFile, natives_blob);
#else
        UNREACHABLE();
#endif
    }

    void V8::SetSnapshotBlob(StartupData* snapshot_blob)
    {
#ifdef V8_USE_EXTERNAL_STARTUP_DATA
        base::CallOnce(&init_snapshot_once, &SetSnapshotFromFile, snapshot_blob);
#else
        UNREACHABLE();
#endif
    }
} // namespace internal

// static
double Platform::SystemClockTimeMillis()
{
    return base::OS::TimeCurrentMillis();
}
} // namespace v8
